Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: mmwrq@cdc.gov. Type 508 Accommodation in the subject line of e-mail.

In April 2004, the Colorado Department of Public Health and Environment (CDPHE) was notified about a boy
aged 3 years with diagnosed tularemia associated with a hamster bite. Tularemia has not been associated previously with
pet hamsters. CDPHE conducted an investigation to determine whether other owners of hamsters were at risk. Clinicians
and public health officials should be aware that pet hamsters are a potential source of tularemia.

During January 2--February 8, the boy was exposed to six hamsters that his family had purchased from a pet store in
the Denver metropolitan area. Each hamster reportedly died from "wet tail disease" (i.e., diarrhea) within 1 week of purchase. One hamster bit the child on the left ring finger shortly
before it died. Seven days later, the child had fever, malaise, painful
left axillary lymphadenopathy, and skin sloughing at the bite site. After treatment with amoxicillin clavulanate failed,
the patient underwent excisional biopsy of a left axillary lymph node 49 days after symptom onset for persistent
painful lymphadenopathy and intermittent fever. Tissue culture yielded a suspected
Francisella tularensis isolate, which was
confirmed by real-time polymerase chain reaction and timed-release fluorescence at the CDPHE laboratory. Convalescent serology
was positive at a titer of 4,096, and the isolate was identified by CDC as type B. No other risk factors for tularemia exposure were identified, including no other animal contact, no exposure to game meat, and no known mosquito, tick, or fly bites.
The patient improved after treatment with ciprofloxacin.

Workers at the pet store reported an unusual number of deaths among hamsters but not other animals during
January--February; no carcasses were available for testing. One of two cats kept as store pets had a positive serologic test for F. tularensis at a titer of 256. Neither cat had appeared ill to store
employees.

Lists of employees, pet suppliers, and customers who purchased hamsters during December 2003--February 2004
were obtained from the store owner. Fifteen of 18 customers were located and interviewed. Eight of these had hamsters that
died within 2 weeks of purchase, but all carcasses had been disposed of and were unavailable for testing. One customer and one employee who had febrile illness after being bitten by hamsters from the store were negative for
F. tularensis by serologic testing. The same customer's hamster was available, and it was also negative for
F. tularensis by serology and culture.

Approximately 80% of the 50 hamsters at the pet store came from customers who had pets with unanticipated litters.
The other 20% were purchased from two small-pet breeders. These breeders were contacted, and neither reported an
unusually high number of deaths of hamsters or other animals. One breeder also supplied animals to two pet stores in Wyoming.
The Wyoming Department of Health had not been notified of any tularemia cases linked to these stores.

Confirmation of a hamster as the infectious source was limited by the delay between the patient's illness onset and
diagnosis and subsequent lack of availability of implicated hamsters for testing. Nonetheless, the hamster that bit the patient was the most likely cause of infection because no other exposures or risk factors were identified. The positive serologic test for F. tularensis in a pet cat at the store suggested that other animals in the store might have been exposed to
F. tularensis. In addition, the proximity of the onset of the patient's illness to the timing of the hamster bite, reports of illness among hamsters, and the deaths of hamsters at the pet store indicated an infected hamster as the likely source of illness. A possible
scenario, similar to an outbreak of tularemia that involved zoo primates
(1), is that infected wild rodents infested the store and
spread the infection to hamsters by urinating and defecating through metal screens covering hamster cages. The infected cat might have had a subclinical or unrecognized illness
after catching or eating an infected wild rodent.

The storeowner was advised to set traps for wild rodents and to inform the state health department of any recurrent
animal deaths or reports of ill customers or staff. No other cases have been identified.

Although tularemia has been associated with hamster hunting in Russia
(2), it has not been associated previously with
pet hamsters in the United States. However, clinicians and public health officials should be aware that pet hamsters might be a potential source of tularemia. Moreover, because
F. tularensis is a potential agent of biologic terrorism
(3), clinicians should have a heightened awareness of tularemia.

Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of
Health and Human Services.References to non-CDC sites on the Internet are
provided as a service to MMWR readers and do not constitute or imply
endorsement of these organizations or their programs by CDC or the U.S.
Department of Health and Human Services. CDC is not responsible for the content
of pages found at these sites. URL addresses listed in MMWR were current as of
the date of publication.

DisclaimerAll MMWR HTML versions of articles are electronic conversions from ASCII text
into HTML. This conversion may have resulted in character translation or format errors in the HTML version.
Users should not rely on this HTML document, but are referred to the electronic PDF version and/or
the original MMWR paper copy for the official text, figures, and tables.
An original paper copy of this issue can be obtained from the Superintendent of Documents,
U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800.
Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to
mmwrq@cdc.gov.